wigglers

Is used to centre over a hole but can also be used to find an edge if the ball is a known diameter. When you're properly centred over the hole you can touch the ball down and it won't go off centre.

Used to centre over a specific point or centre pop mark in a workpiece.

Used to mount a DTI onto although I can't imagine anyone wanting to bother doing so. It's easy enough to mount one on any bit of bar in a chuck. I also wouldn't be confident that the arm and hence the DTI wouldn't move in the wiggler body unless it was screwed up really tight.

In all cases except 4 you get the wiggler running true by spinning it at about 1000 rpm and nudging it with a pencil until it stops wobbling and then bring it to the workpiece.

Can't say I ever use them though. I chuck a bit of 3/8" silver steel in a collet and bring it to the edge I'm trying to zero on and then set the DRO when it just touches. Might not be quite as accurate but I reckon it's good to a couple of thou or less. For finding a point I have another bit of silver steel turned to a point.

I did once think about rigging up a battery and torch bulb with a couple of crocodile clips so that when the silver steel touched the edge it completed the circuit and the bulb lit up. Never got roundtuit though but in theory it should be a great method. Alternatively you could use a multimeter set on ohms with one clip on the silver steel and the other on the workpiece. Probably even easier to set up as everything you need is built in.

Thanks Dave,

The way I was tought to use the cylinder one was to bring it up against the edge of the work whilst spinning. You will see the wobble getting less and less until the thing is spot on centered. A slight nudge more and the wiggler will then shoot off to the side. At that point, remove from chuck, index over exactly half the distance and zero the dials. I have never used any of the other 3.

When using them, do you still have everything spinning (apart from No.4)

I use the ball for all edge finding apart from finding the edge of a horizontal bar. The cylindrical one is needed here to ensure the tangent. I do little marking out so the point has not been used. Bent one not stiff enough for a clock IMHO

A decent quality ballrace locktited onto a piece of silver steel makes a good edge finder,when the outer race stops spinning it's touching the edge.

Learnt that from Mr. JS.

Allan

David,

Check the diameter of the ball. I found out the hard way that the ball on the set I had bought was not 0.25" (as stated on the blurb) but a metric value closer to 0.20" :-)

Jim.